FIG. 1 illustrates a view showing the concept of a related-art method for separating audio sources. In FIG. 1, s1, s2, and s3 are three (3) different audio sources, and x is a mixed audio signal, That is, x is a mix signal of s1, s2, and s3.
As shown in FIG. 1, there is no overlap among the audio sources s1, s2, and s3. That is, the audio sources s1, s2, and s3 are independent of one another.
In this circumstance, there is no problem in separating the audio signal x into the audio sources s1, s2, and s3. This is because an audio component constituting the audio signal x can be matched with one of the audio sources s1, s2, and s3.
However, the audio signal x and the audio sources s1, s2, and s3 shown in FIG. 1 are the ideal or very special case. In practice, the audio signal x and the audio sources s1, s2, and s3 are in the state shown in FIG. 2.
That is, the audio sources s1, s2, and s3 are not completely independent of one another. That is, there is an overlap among the audio sources s1, s2, and s3. In this circumstance, there is no problem in mixing the audio sources s1, s2, and s3 into the single audio signal x.
However, a problem arises when the mixed audio signal x is separated into the audio sources s1, s2, and s3. This is because an audio component corresponding to the overlapping area of the audio sources s1, s2, and s3 cannot be matched with one of the audio sources s1, s2, and s3.
Due to this problem, an audio source separation algorithm processes the audio signal x and the audio sources s1, s2, and s3 on the assumption that the audio signal x and the audio sources s1, s2, and s3 are in the state shown in FIG. 1 even if the audio signal x and the audio sources s1, s2, and s3 are actually in the state shown in FIG. 2.
Since the audio sources are separated without considering the real state of the audio signal and the audio sources, excellent audio source separation performance would not be guaranteed and it is.